Transformer-core construction.



No. 896,983; PATENTED AUG. 25, 1908 J. J. FRANK.

TRANSFORMER com: GQNSTRUGTION,

APPLICATION FILED MAY 1, 1907.

Wnwcaac: INVE'NTEIR U ITED STATES PATENT OFFICE. r JOHN J. FRANK, OF soHENncTAnY, NEW YORK, AssicNon TO GENERAL ELECTRIC coMP NY, A CORPORATION or ,NEW YORK. I

TRANSFORMER-GORE CONSTRUCTION.

To all whom "it may concern: I

Be it known that I, JOHN J FRANK, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Transformer Core Construction, of which the following is a specification.

My invention relates to the construction of jointed and laminated magnetic cores and its object is to provide a novel core construction which decreases materially the cost of manufacture.

-While my invention is applicable to any jointed and laminated magnetic core it is particularly advantageous when applied to the construction of cores for core-type transformers. These transformers are ordinarily assembled by first assembling the legs of the core, then placing the transformer coils on the legs, and then interleaving the laminae forming the ends of the core with the ends of the laminae forming the legs so as to close the magnetic circuit of the core. The lower end laminations may be assembled before the coils are placed on the legs, but the upper end laminations cannot be assembled until after the coils are in place.

In order to permit the interleaving of the laminae at the joints between the legs and end pieces, the legs are ordinarily made up of small bundles of laminae, alternate bundles being oppositely dis laced longitudinally, so that spaces are le t between the ends of the bundles displaced in the same direction, for receiving the bundles of the end laminae.

In practice it has been found that after the legs are assembled and before the end laminae are placed in position the outer laminae of each bundle comprising the legs, spread out at their ends to meet theouter laminae of adjacent bundles and to close the ends of the spaces left for the reception of the end laminae.

In order to enable the workman to separate the ends of the bundles so as to insert the end laminae it has been customary to out ofi ,a corner of the laminae and to reverse the adjacent bundles that are similarly displaced in assembling the legs of the core, so that the notches formed by cutting off the corners of the laminae mark ofi each bundle from those on each side of it. Cutting'off the corners of the laminae, as above described, requires an extra Operation or an expensive die and specification of Letters Patent.

Application filed. May 1, 1907. Serial No. 371,285.

Patented Aug. 25, 1eos.

materially increases the cost of manufacture.

The object of my invention is to secure the same result with a cheaper construction.

I accomplish this by cutting a notch in one end of each lamina between its side edges,

the notch being located dissymetrically or mother words off center. This notch may be stamped out at the same time the lamina as a whole is stamped out, so that the cost of the separate operation which has been required heretofore to cut off the corners or the cost of the expensive die required for this purpose are saved.

My invention will best be understood by reference to the accompanying drawings in which Figure 1 shows a transformer provided with a core constructed in accordance with my invention; Fig. 2 shows a perspective view of the core with the coils removed;

and Fig. 3 shows a portion of one of the legs of the core illustrating the method of forming the leg. 4 v

a In the drawings, A represents the transformer coils which are mounted on a closed jointed magnetic core, formed of the legs B B, carrying the coils, and end pieces C C joining the ends of the legs. The sections of which the core is thus formed are interleaved at the joints, as is clearly shown in Fig. 2. Each lamina in each leg is provided with a notch d which is cut out at one end of the lamina between its side edges but on one side of the center line of the lamina.

In assembling the legs of the core small bundles of similarly arranged superposed laminae are assembled as shown in Fig. 3. Alternate bundles, such as b b are displaced longitudinally in opposite directions. To facilitate this displacement holes 6 may be punched in the laminae when they are stam ed out so that the laminae ma semb ed in the usual manner on olts or guide-rods, and by turning alternate bundles end for end'the desired longitudinal displacebe asable tool in one of the notches (1, thereby o ening the space between the bundles for t 1e insertion of the end laminae.

For the purpose of clear illustration the laminae and bundles are shown much thicker and the total number of bundles much less than would be the case in practice, so it will be understood that the drawings are largely diagrammatic.

What I claim as new, and desire to secure by Letters Patent of the United States, is,-

1. A jointed and laminated magnetic core, the laminae being interleaved at the joints and a ortion of said laminae having notches located dissymmetrically at the interleaving ends of the laminae between their side edges.

2. A jointed and laminated magnetic core, the laminae being interleaved at the joints and having square corners, with notches located dissymmetrically at the interleaving ends of a portion of the laminae.

3. A closed, jointed, magnetic core composed of laminated sections interleaved with each other at the joints, a ortion of said sections being each composed of bundles of laminae provided with notches dissymmetrically located at their ends between their side edges, alternate bundles being oppositely displaced longitudinally and adjacent bundles displaced in the same direction being relatively reversed so as relatively to displace their notches laterally.

In witness whereof, I have hereunto set my hand this 30th day of April, 1907.

JOHN J. FRANK.

Witnesses:

BENJAMIN B. HULL, HELEN ORFORD. 

